Continuous Mott transition in moir\'e semiconductors: role of long-wavelength inhomogeneities

TL;DR

This paper investigates how long-wavelength inhomogeneities influence the continuous Mott transition in moiré semiconductors, providing insights into experimental puzzles and extending theoretical models to include disorder effects.

Contribution

It introduces a framework incorporating long-wavelength inhomogeneities into the study of Mott transitions, highlighting their impact on transport properties near criticality.

Findings

Inhomogeneities significantly alter transport near the transition.

Random resistor network models reveal differences from simple percolation.

Results align with experimental observations of continuous transitions.

Abstract

Recent experiments in moir\'{e} transition metal dichalcogenide materials have reported the observation of a continuous bandwidth-tuned transition from a metal to a paramagnetic Mott insulator at a fixed filling of one electron per moir\'{e} unit cell. The electrical transport measurements reveal a number of puzzling features that are seemingly at odds with the theoretical expectations of an interaction induced, but disorder-free, bandwidth-tuned metal-insulator transition. In this work, we include the effects of long-wavelength inhomogeneities, building on the results for a continuous metal-insulator transition at fixed filling in the clean limit. We examine the effects of meso-scale inhomogeneities near the critical point on transport using the framework of random resistor networks, highlighting the salient differences from a simple percolation-based picture. We place our results in the context of recent and ongoing experiments.